I had the same problem. I didn’t have an orphaned post. I did figure out that if I created a new page or blog entry, the problem went away. If I deleted the new test page, the problem came back. That’s good enough for me.
If I may speculate, there’s probably a data integrity issue where the data doesn’t quite match expectations in the code. It would be nice to have a script that checks integrity on the entire database, but I know I don’t have time to bang it out.
